The present invention is directed to a spray nozzle, particularly adapted for spray guns. The invention comprises a rotary element placed within a central body. The rotary element is traversed by a channel having a spray orifice. A safety tip is arranged at the front of the central body between the rotary element and the diffuser of the gun. The spray gun is provided with a diffuser on which the central body is secured. The central body has a central bore corresponding to the channel of the spray orifice of the rotary element. A fluid tight joint structure traverses the bore in the central body.
There are a large number of so-called safety spray nozzles. They are provided at their front with a tip to protect against contact of the user with the fluid sprayed, at least over a relatively short distance in front of the spray orifice. The spray particles emerge from the spray orifice at very high speed since spray nozzles of this type are generally used for the spraying of paint under high pressure. Spray nozzles of this type must, therefore, be and remain tight after repeated rotations of the rotary element in the central body and after numerous diassemblies required for cleaning or for changing the atomizer and, therefore, changing the rotary element.
The principal problem raised by these nozzles which are intended to operate under high pressure is to obtain sufficient tightness of the seal without using excessive clamping force.
Furthermore, the rotary element and its atomizer must be capable of being easily changed.
The prior art has suggested various solutions to these problems but have not solved them: U.S. Pat. No. 3,955,763 describes a spray nozzle intended to be fastened to the diffuser of a spray gun, the nozzle comprising a rotary element in the form of a ball having a spray orifice provided in a circular conduit. This nozzle comprises a housing surrounding the rotary element and a sealing member placed in the housing and applying itself tightly against the rotary element. The housing, the rotary element and the sealing member are assembled in a single operation by screwing onto the diffuser of the spray gun. When the user desires to change a nozzle, he must separate the nozzle from the diffuser of the gun and then assemble the different parts before proceeding in a single operation, with the remounting of the nozzle on the diffuser of the gun. The user may encounter difficulties in this operation since the parts constituting the nozzle must be in perfect registry with each other before proceeding with the clamping of the nozzle.
U.S. Pat. No. 4,165,836 describes a rotary spray nozzle comprising a cylindrical rotary element and a sealing joint intended to prevent leakage of fluid under high pressure. It comprises a metal bearing member which bears against the rotary element and a spaced elastic element clamped between the metal bearing element and the diffuser of the spray gun in order to form a fluid joint and at the same time assure the operation of a damper which protects the metallic bearing element from excessive clamping forces.
The nozzle described in U.S. Pat. No. 4,165,836 has the same drawbacks as the nozzle described in U.S. Pat. No. 3,955,763. U.S. Pat. No. 4,484,707 describes a spray nozzle which contains an orifice member disposed within a channel in a housing body. This design permits easy substitution of different sized orifice members. Moreover, the disclosed rotary element can be rotated to reverse the orifice for cleaning. Furthermore, the clamping nut of the nozzle is integral with the latter and cannot be changed. This nozzle is, therefore, intended to be mounted on a single type of gun and thus cannot be used on all existing guns.